JP4326459B2 - Burner control device - Google Patents

Description

  The present invention relates to a burner control device for a power plant using a boiler, and more particularly to a burner control device that suitably controls the amount of combustion air in accordance with a plant state signal, for example, the value of a boiler load signal and the type of fuel used.

Conventionally, in a power plant using a coal-fired boiler, as a burner operation control, when starting and stopping a pulverized coal mill, which is a means for supplying fuel, that is, by igniting and extinguishing a pulverized coal combustion burner. when and, by reducing narrow the amount of air supplied for combustion, it has been made possible to reduce of the NO _X in the exhaust gas.

Patent Document 1 discloses a technique for narrowing the supply amount of secondary air for combustion and flame holding when a pulverized coal combustion burner is ignited and extinguished. Patent Document 2 discloses an opening degree of an air register that supplies combustion air between low load operation and high load operation when low load operation and high load operation are switched according to the supply amount of pulverized coal. There is a description about changing at a constant ratio.
Japanese Patent Laid-Open No. 7-312314 JP 2002-39526 A

  By the way, in this kind of power plant, not only when coal is burned exclusively as a fuel, but also simultaneous combustion of coal and oil (light oil or heavy oil) or oil burning may be performed. For example, at the start of ignition, there may be a case where coal and oil are burned simultaneously so that stable ignition can be achieved. Or, when there is some trouble with the supply of coal, there is a case where the oil is burned exclusively. As described above, when the type of fuel to be burned is different, an appropriate supply amount of combustion air is different, and there is a problem that complicated control is required as control of the supply amount of air.

  In addition, the appropriate supply of combustion air differs between low-load operation and high-load operation. Considering low-load operation and high-load operation, more complex control of air supply is required. There was a problem to become.

In particular, in an actual power plant, a plurality of combustion burners are prepared, and in order to appropriately manage the plurality of burners in accordance with the operation status, it is necessary to control the supply amount of complicated air. When the control of the plurality of burners in a homogeneous state, always occurs amount of the NO _X by the combustion in the individual burners, there be a situation where it can not be said that an optimally controlled.

The present invention has been made in view of the foregoing, an object of relatively simple control, to provide a burner control device capable of the fuel by properly combusted to reduce NO _X generation amount.

The present invention relates to a burner control device for controlling the operation of a plurality of burners provided with a fuel valve for controlling the supply of fuel and an air register for controlling the supply of combustion air, the burner having prepared coal and oil as fuel. In the control device , when the burner operation command output unit commands the ignition state or the fire extinguishing state during the coal burning , the opening of the air register is individually or in groups based on the operation load state determined by the operation state determination unit. Select and control the opening at low load and opening at high load prepared in advance, and when opening coal and oil simultaneously or exclusively burning oil, the opening is individually or grouped regardless of the load. It is designed to be set in units .

According to the present invention, for a plurality of burners, the air supply amount is controlled while the appropriate air register opening is set individually or in groups at low load and high load. ensuring optimum air flow rate adapted to the driving situation, there is an effect that it is possible to effectively reduce the NO _X generation amount.

  Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a diagram showing a configuration example of a power plant provided with the burner control device of the present embodiment. Referring to FIG. 1, the power plant controlled by the burner control device of this example includes a burner control device 1 that controls the operation state of the burner, a boiler furnace 3 of the power plant, and a boiler furnace 3. A plurality of oil burners 41a to 41n and coal burners 51a to 51n to be inserted (here, n: n is an arbitrary value of 2 or more), and an oil supply pipe for supplying oil as fuel to each oil burner It comprises a passage 71, a coal supply line 72 for supplying coal as fuel to each coal burner, and a combustion air supply line 73 for supplying air for burning the fuel. The air corresponding to the combustion amount at that time is supplied from the blower 74 to the combustion air supply pipe 73. The n oil burners 41a to 41n and the n coal burners 51a to 51n are installed one by one.

Burner control device 1, for example, an external signal input unit 11 for inputting an external signal such as the operation load signal and NO _X values and used fuel type, burner operation the operating state of each burner in accordance with the external signal is set A schedule unit 12, a burner operation command output unit 13 that outputs an operation command for each burner, an operation state determination unit 14 that determines the operation state of the power plant, and a plurality of individual burner control units 20a that control the operation of each burner. ~ 20n.

  The external signal input unit 11 inputs a signal related to an operation load, which is a load that is an operation target of the plant, and an exhaust gas NOX value from an operating furnace, and burner driving units 41a to 41n and 51a to 51n described later. A signal relating to the fuel type, which is a feedback signal from, is input. In addition, an external signal such as a load signal from the outside, which is another device such as a detector for determining the plant state or a boiler control device, is also input.

  When the operation state determination unit 14 determines that the low load operation is performed based on the external input signal, the operation state determination unit 14 is a signal for opening the air register to the air register control unit 22 in each of the individual burner control units 20a to 20n. Is output. Here, as the low load operation, for example, the operation load is in a state of 55% or less of the rated load, and the operation load exceeding 55% of the rated load is defined as the high load operation. The operation load is adjusted, for example, by selecting the number of burners to be burned out of a plurality of burners 41a to 41n and 51a to 51n. That is, when operating in a state close to the rated load using coal as fuel, control is performed so that almost all the coal burners 51a to 51n are burned, and the number of burners to be burned is reduced as the operating load is reduced.

  A plurality (n) of individual burner controllers 20a to 20n are provided corresponding to the number of burners 51a to 51n. However, as will be described later, a plurality of burners 51a to 51n (and 41a to 41n) are divided into a plurality of groups, and individual burner control units 20a to 20n are provided by the number of the groups, and the burners are grouped. You may make it control.

  About the structure of each individual burner control part 20a-20n, the insertion or extraction operation | movement of the burner in the furnace 3 according to the operation state of a burner, the supply of the fuel to a burner, and the supply of fuel combustion air are controlled. To do. In such a power plant, a burner gun is inserted into the boiler furnace 3 and the supplied fuel and combustion air are mixed and sprayed into the furnace 3 to form a flame. When the boiler is under a low load, a burner corresponding to the load is selected and ignited according to a predetermined schedule, and the remaining burners are extinguished. When the burner is extinguished, the fuel supply valve (to be described later) is closed to shut off the fuel input from the burner and the flame in the boiler furnace 3 disappears.

  The individual burner control units 20a to 20n have basically the same configuration. Here, the configuration of the individual burner control unit 20a will be described. The oil burner 41a and the coal burner into the furnace 3 according to the operation state of the burner. The burner operation control unit 21 controls the insertion or extraction operation of the 51a and controls the burner driving units 31a and 33a. The burner drive unit 31 a drives an oil supply valve 32 a provided in the fuel supply pipe 71. The burner drive unit 33 a drives a coal supply valve 34 a provided in the fuel supply line 72.

  In the boiler furnace 3, the air from the combustion air supply pipe 73 is supplied in the vicinity of the installation positions of the oil burner 41a and the coal burner 51a. An air valve 36a is installed. The air valve 36a is driven by an air valve driving unit 35a. The air register controller 22 controls the driving of the air valve 36a in the open / closed state by the air valve driver 35a.

The air register control unit 22 has an air register low load opening command generation unit 23, an air register high load opening command generation unit 24, and an air register coal-fired as air register opening command generation means. The other-time opening command generation unit 25 and the switches 26 and 27 are provided, and corresponding generation data are stored in advance in the respective generation units 23, 24, and 25. The data in this opening, the burner 41a air register (air valve 36a) is installed to the air register control unit 22 controls, was determined from each of the combustion state of the 51a, when the NO _X generation amount is the lowest The opening of the air valve 36a is stored. In FIG. 1, the opening command generation units 23, 24, and 25 are described as individual means. However, for example, each opening command generation unit 23, 24, and 25 is divided into one memory area. Instead of selecting the output by the switching units 26 and 27, the data to be output from the memory may be selected.

  As for the output of the registration low load opening command generation unit 23 and the output of the air register high load opening command generation unit 24, data indicating whether the operation is low load operation or high load operation supplied from the operation state determination unit 14 Thus, the opening degree command corresponding to the load state is selected by the switch 26. Further, the output of the switching device 26 is supplied to the switching device 27 and is selected as the output of the opening degree command generation unit 25 other than the air register coal combustion only according to the fuel information supplied from the operation state determination unit 14. In the switch 27, the output of the switch 26 is selected at the time of coal-only burning, and the output of the generating unit 25 is selected at the time of oil-only burning and simultaneous combustion of coal and oil.

  The other burner control units other than the individual burner control unit 20a are configured in the same manner. For example, as shown in FIG. 1, the individual burner control unit 20n performs drive control of the burner drive units 31n and 33n and drive control of the air valve drive unit 35n, and provides an oil supply valve 32n, a coal supply valve 34n, and an air valve. The opening of 36n is controlled.

  Next, a state in which the opening degree of each of the air valves 36a to 36n is controlled by the individual burner control units 20a to 20n will be described with reference to the flowchart of FIG. First, it is determined whether or not the current combustion state is coal-only combustion according to the fuel information supplied from the operation state determination unit 14 (step S11). Based on this determination, selection by the switch 27 is performed. If it is coal-fired, it is determined whether the operation is low load operation or high load operation based on the operation load information supplied from the operation state determination unit 14 (step S12). Based on this determination, selection by the switch 26 is performed.

  On the basis of these determinations, when it is determined that the coal-fired operation is a low load operation, the output of the Aregist low load opening command generation unit 23 is supplied to the air valve drive unit side (step S14). When it is determined that the operation is a high load operation due to the coal burning, the output of the open register command generation unit 24 at the time of the high load is supplied to the air valve drive unit side (step S15).

  If it is determined in step S11 that the current combustion state is not coal-fired, it is determined whether coal and oil are simultaneously burned or oil-only firing (step S13). Here, when it is determined that coal and oil are simultaneously burned, the opening command for simultaneous combustion stored in the opening command generation unit 25 other than the air register coal combustion is output, and the air valve driving unit side Is supplied (step S16). When it is determined that the oil-only firing is performed, the opening command for oil-only firing stored in the opening command generation unit 25 other than the air register coal-burning is output and supplied to the air valve drive unit side (step) S17).

When the operation control is performed as described above, the operation state determination unit 14 determines that the operation load is a low load operation of 55% or less of the rated load based on the external input signal. A signal is output to the register control unit 22 for opening the air register. As a result, when the operating load is 55% or less of the rated load, the air register is controlled in the closing direction, the combustion air is throttled, and only the amount of air necessary for operation at a low load is supplied into the furnace 3. The generation of NO _X exceeding the regulation value can be suppressed. The amount for the amount of air register (air valve) is narrowed, and which was determined to comprise the most NO state generation is reduced in _X combustion at low load the burner made in advance the air register and paired this time since it is set to be in a state generate less most NO _X per individual burners.

  Further, for example, when it is determined that the fuel burned in the burner is coal, a signal for opening the air register to the air register control unit 22 to supply an air amount necessary for the coal to burn well is provided. When it is determined that the oil is being burned exclusively with oil or being simultaneously burned with oil and coal, a signal for opening the air register to the air register controller 22 to supply an air amount necessary for the oil to burn well is provided. Is output. As a result, the required amount of air corresponding to the difference in the fuel used is supplied into the furnace 3 and a good burner combustion state can be maintained.

  Here, a specific control example of the operation state will be described. For example, in a boiler with a rated load of 1,000 MW (MW: boiler output value), a load signal during a boiler operation at a low load is less than 550 MW. If it is a value, the air register control unit 22 for the igniting burner selects and outputs an air register low load opening command to control the air register to the low load opening. Also, if the load signal during boiler operation at normal load or high load is a load value of 550 MW or more, the air register high load opening command is selected and output to open the air register at high load Control every degree. The selector 26 selects the air register low load opening command and the air register high load opening command. Further, the switch 27 includes a command in which one of the air register low load opening command and the air register high load opening command is selected by the switch 26, and an air register coal non-combustion opening command. An opening command when the air register coal is not fired from the generating unit 25 is input, and any command is selected and output based on the operating state information from the operating state determining unit 14.

  Therefore, the air register control unit 22 outputs the air register opening command selected by the switch 26, for example, when the burner fuel is coal and the coal burner is being burned exclusively. Also, if the fuel used in the burner is oil and the oil burner is burned exclusively, or if the oil burner and the coal burner are burned at the same time, the coal burner is being burned simultaneously, other than air register coal burning The hour opening command is selected and output, and the air register is controlled to an opening other than coal-fired.

  Here, in this example, an air register low load opening command is output during low load operation (generally in a range between 0 to 55% of the rated load) such as an initial startup process in the boiler furnace 3, The air valves 36a to 36n constituting the register are operated to the low load opening degree set individually for each air valve.

  In addition, during high load operation (approximately in the range of 55 to 100% of the rated load) after the start-up of the boiler furnace 3 is completed, that is, when the load exceeds 550 MW, the air register high load opening degree command Is output, and the air valves 36a to 36n constituting the air register are operated to the high load opening degree set individually for each air valve.

  The selection of the air register low load opening command and the air register high load opening command is performed according to the load signal described above. In the case of a burner that is burning with oil or a burner that burns oil and coal at the same time, an opening command is output when the air register is not coal-fired, and the air register is operated to an opening when the coal is not fired. The

  As explained above, in addition to the air register non-coal opening command when the burner is burning exclusively with oil or during simultaneous combustion of oil and coal, the air register is low when the burner is burning only with coal and during low load operation. There are 3 types of commands: opening command at load and air register high load opening command that corresponds to burner being burned with coal and high load operation, and switching these multiple air register operation commands depending on the boiler operation status By properly using them, the air flow rate into the boiler furnace 3 can be suitably controlled and optimum burner ignition / extinguishing control can be performed with a simple configuration that does not require complicated control.

  In the configuration described in the above-described embodiment, it is a case where the boiler is based on the basic combustion of coal, and combustion using only oil or simultaneous combustion of oil and coal is an auxiliary use. In the case of combustion alone and during simultaneous combustion of oil and coal, the opening degree of the air valves 36a to 36n constituting the air register is not changed between low load and high load. Even when the fuel is burned, the opening of the air register may be changed between a low load and a high load.

  Further, in the above-described embodiment, the air register is controlled corresponding to each burner in the furnace. For example, a group is formed for each of the plurality of burners, and the group is set as a unit. The opening of the air register may be controlled.

The conditions for selecting one of the air register low load opening command, the air register high load opening command, and the air register coal non-combustion opening command other than the load signal and the type of fuel used are as follows. In some cases, the NO _X value may be used, and the furnace temperature, the number of burned burners, and the coal type may be used.

When the NO _X value is used as a condition, for example, the NO _X value is measured in real time during combustion, and the opening degree may be adjusted as needed so that the measured NO _X value decreases. . For example, as shown in the flowchart of FIG. 3, to measure the NO _X value in operation at any time (step S21), and determines whether or not NO _X value measurement is proper range (step S22), and proper If not in the range, by adjusting the opening degree of the air register (step S23), to execute the nO _X value measured in step S21 again.

By making correction based on the NO _X value measured in real time in this way, more efficient operation becomes possible. Even when the correction is performed based on the NO _X value measured in real time, the air register is controlled individually for each burner or for each burner in units of groups, so that more appropriate control can be performed.

It is a block diagram which shows the structural example of the burner control apparatus by one embodiment of this invention. It is the flowchart which showed the opening degree setting process example of the air register by one embodiment of this invention. It is the flowchart which showed the example of a process in the case of correct | amending control by one embodiment of this invention in real time.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Burner control apparatus, 3 ... Boiler furnace, 4 ... Wind box, 11 ... External signal input part, 12 ... Burner operation schedule part, 13 ... Burner operation command output part, 14 ... Operation state determination part, 20a-20n ... Individual Burner control unit, 21 ... burner operation control unit, 22 ... air register control unit, 23 ... air register low load opening command generation unit, 24 ... air register high load opening command generation unit, 25 ... air register coal combustion Non-hour opening command generation unit, 26, 27 ... switch, 31a-31n ... burner drive unit, 32a-32n ... oil supply valve, 33a-33n ... burner drive unit, 34a-34n ... coal supply valve, 35a-35n ... Air valve drive part, 36a-36n ... Air valve, 41a-41n ... Burner for oil, 51a-51n ... Burner for coal, 71 ... Oil supply line, 72 ... Coal supply line, 73 ... Combustion air supply Conduit, 74 ... blowing part

Claims (2)

A burner control device for controlling the operation of a plurality of burners provided with a fuel valve for controlling the supply of fuel and an air register for controlling the supply of combustion air ,
In the burner control device prepared with coal and oil as the fuel ,
An operation state determination unit that determines an operation state based on an external signal;
A burner operation command output unit that commands the operation of each burner individually or in groups based on the external signal;
A burner operation control unit that controls the operation of burners individually or in units of groups based on the burner operation command, and an individual burner control unit that includes an air register control unit that controls opening and closing of the air register,
The individual burner control unit determines the opening of the air register based on the operating load state determined by the operation state determination unit when the burner operation command output unit commands an ignition state or a fire extinguishing state during coal combustion. , Select and control from the opening at the time of low load and the opening at the time of high load prepared individually or in groups ,
A burner control device that sets the opening degree individually or in groups regardless of the load during the simultaneous combustion of coal and oil or when the oil is burned exclusively . The burner control device according to claim 1,
The low-load opening and high load of the opening degree, individually or based the NO _X generation amount due to combustion in the burner of the group, the burner control unit, which is a pre appropriately adjusted value.

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